This invention relates to golf putters and golf clubs, specifically to an improved method for making golf clubs and golf club putters from extrusions with many embodiments and making golf putters with a high resistance to twist upon impact.
The art of hitting a golf ball with a golf club head produces a moment (twisting force) if the ball is not struck at the club""s center of gravity. This is a so called xe2x80x9coff-center hit.xe2x80x9d The twisting force opens or closes the club head face at impact so that the actual initial trajectory of the ball is not the intended trajectory. Unfortunately, it is unlikely that a golfer consistently hits the golf ball at precisely the center of gravity every time. Thus, one of the goals of golf club designers is to decrease the likelihood of off-center hits adversely affecting the trajectory of the golf ball by minimizing the effects of the twisting moment.
There have been many different design approaches to solve the no-twist problem for golf putter heads and golf clubs in general. These approaches may or may not be desirable from a manufacturing point of view. While it is effective to use exotic materials to solve the twisting moment problem by using light weight materials near the center of gravity of the club and very dense materials (tungsten for example) at the outer ends of the putter head, it is not cost effective to do so. Further, extensive machining of club heads from castings or billet materials can produce dynamically effective solutions, but not necessarily cost effective ones.
(Investment) casting of golf putter heads is the normal manufacturing method used today. With investment casting, designers strive to achieve the goals of the right dynamics and good looks while maintaining low manufacturing cost. Casting, in general, is a low cost for high volume approach to producing golf putters heads as well as irons and woods. However, casting these heads does not control the grain structure of the head since casting produces fairly homogeneous structures with randomly oriented grain structure. Further, casting methods may also produce voids in the heads as gas bubbles form in the cooling casting. Voids affect the dynamics, strength, sound, and uniformity of golf club heads, none of which is desirable.
The orientation of grain structure is desirable in ones own experience apart from golf clubs. Base ball bats are selected for gain structure, as are wooden mallets, wooden beams, wooden block floors for heavy machinery, machined metallic plates, etc., all of which are selected for their grain structure. From these examples, as far as the orientation of the grain, a grain structure which is oriented in line with the line of impact (baseball bats excepted) seems to be the most effective way for energy transfer. Croquette mallets or wooden mallets sound solid (and hit solid) because of their aligned grain structure. Thus, it seems that a golf putter head with an aligned grain structure would be also more effective in the transfer of energy.
Another important system of golf clubs (and golf putter heads usually) is the alignment system which helps the golfer align the club face perpendicular to the intended line of the golf ball. A simple analysis of the problem shows that a alignment error of one degree would produce an error of 10 cm (four inches) on a perfectly flat surface in a roll of 6 meters (20 feet). This error is approximately the width of the cup in the green. Alignment marks have been incorporated into golf putter heads for some time in order to reduce these alignment errors. It seems reasonable to incorporate the alignment principal into the design of the entire golf putter head: that of parallel and perpendicular lines and surfaces.
It also seems unlikely that one weight (mass) golf putter, one face loft, one shaft lie angle, one shaft length putter will suit all golfers. There are hundreds of variations (if not thousands) of mass, loft, lie, shaft length available to golfers today. It is desirable to be able to accommodate as many different models (with distinct features) into one basic design as possible. This would be done for market penetration reasons if not for manufacturing reasons. Thus, a design which allows for multiple configurations without any or few changes in machining would be very desirable.
Style considerations for golf club heads and golf putter heads specifically are restricted in at least two ways. One, the USGA will not allow but so much a departure from past conforming designs. Two, stylistic considerations from the users point of view may require proportionally and finish beyond that of just club head performance.
In conclusion, a most effective design would then incorporate all of the above, and achieve a dynamically sound, cost effective, uniform, solid feeling, easy to align, golf putter design which can be customized to many different golfers.
The following previous patents by other inventors have attempted to solve one or more of the above goals. None of the previous inventions achieve all of these goals. A short description of the more notable applicable inventions follows.
U.S. Pat. No. 4,714,252 to Roraback, Harry G. (Dec. 22, 1987): A golf putter with ball bearing heel-toe weight inserts is described in Roraback (U.S. Pat. No. 4,714,252). The ball bearings, being less dense than other materials such as lead, are located in hemispherical cavities running from the top surface to the sole. This putter lacks high mass moment of inertial achievable with other designs.
U.S. Pat. No. 4,898,387 to Finney, Clifton D. (Feb. 6, 1990): Finney (U.S. Pat. No. 4,898,387) describes a cast aluminum putter head with only the toe section containing tungsten like inserts (in the abstract lead inserts are described). This is an extremely complex head with many machining steps. It also appears to have a fairly flexible hosel considering the mass moment of inertia claimed.
U.S. Pat. No. 4,693,478 to Long, Dabbs C. (Sep. 15, 1987): A offset hosel (towards ball) with severe face balance is described in Long (U.S. Pat. No. 4,693,478). The higher moment of inertia is achieved by the severe machining of an aluminum casting at the back of the putter head. The face balance is achieved with a large face bias offset hosel. This is an example of a single-sided, face-balance putter head. Mention is made for different masses; however, with the offset hosel design, no mention is made as to the design being able to accommodate different face lofts and shaft lies while achieving the same balance.
U.S. Pat. No. 5,131,656 to Kinoshita, Frank (Jul. 21, 1992): Another one striking face heel-toe weighted golf putter head is described in Kinoshita (U.S. Pat. No. 5,131,656). This putter is claimed to be so called xe2x80x9cgravity balanced xe2x80x9d by Kraneberg below (herein we use center balanced) but is claimed to be face balanced by Kinoshita. A center (gravity) balanced putter hangs in no preferred orientation when the putter""s shaft is placed on a flat surface normal to the direction of the force of gravity. This is one of the few if only reference to such a balance method. The Kinoshita putter has a hosel to attach the putter shaft to the putter head. The addition of a hosel increases the mass of the putter while minimally increasing the mass moment of inertia about the shaft, both of which are not desirable. Further, the complexity of the hosel, either in the machining or the casting of the putter head, does not warrant the addition of a hosel versus a direct attachment. The hosel design complicates the incorporation of different shaft lies. The Kinoshita invention does appear to have a constant radius sole, but no claim is made for this characteristic.
U.S. Pat. No. 5,340,106 to Ravaris, Paul A. (Aug. 23, 1994): Ravaris (U.S. Pat. No. 5,340,106) describes a design of a putter whose shape alone moves material to the heel and toe in order to increase the moment of inertia. However, this putter also has runners on the sole which would require an exact match of the shaft lie to a particular golfer to prevent abnormal scuffing of the putter head.
U.S. Pat. No. 5,290,035 to Hannon, Richard H; Schmidt, Jacob. H. (Mar. 1, 1994): A neutral balanced putter is described in Hannon (U.S. Pat. No. 5,290,0350). The description and figures describe a center balanced, one putting face, putter head. The putter is not symmetric about an axis which will require two different blanks for left and right hand putters. The mass and inertia increasing insert chambers run from the sole to top of the putter head and are only a golf ball width apart, which limits the potential mass moment of inertia with respect to the total putter head mass. Also, the chambers are varied in volume so as to balance the rotation of the putter head about the shaft. This volume changes requires another machining setup with possible different tools.
U.S. Pat. No. 5,078,398 to Reed, Timothy R.; Karner, James E. (Jan. 7, 1992): Reed (U.S. Pat. No. 5,078,398) describe a relatively high-moment of inertia golf putter head with claimed center balancing. A machined or casted void is filled with low density material (urethane) at the center of the head. This is a classic cavity-backed, hosel-to-shaft attachment, single striking surface, golf putter head. This design requires a mirror image casting for the opposite hand version, plus it has highly machined surfaces of difficult to machine stainless steel. It is likely that this putter is in fact face balanced, not center balanced; further keeping the same balance for different face lofts and shaft lies would require a different hosel location for every combination.
U.S. Pat. No. 4,325,553 to Taylor, Dale W. W. (Apr. 20, 1982): Another cavity backed, face balanced putter with claimed high mass moment of inertia is described in Taylor (U.S. Pat. No. 4,325,553). It has one striking face and three weight insert cavities. The center weight cavity is not as effective as heel-toe placed cavities as far as enhancing the inertial-to-mass ratio. A bent shaft is required for face balancing of the putter. No mention is made of materials or of methods of casting or machining this putter head with its complex shapes and cavities.
U.S. Pat. No. 4,444,395 to Reiss, Morton M. (Apr. 24, 1984): A heel-toe weighted putter with changeable heel-toe inserts is described in Reiss (U.S. Pat. No. 4,444,395). This putter does describe different possible widths and depths. However, no mention of different face loft or shaft lie is made and the putter head is not extruded.
U.S. Pat. No. 4,508,350 to Duclos, Clovis R. (Apr. 2, 1985): An aluminum casting putter head is described in Duclos (U.S. Pat. No. 4,508,350). This face balanced, cavity backed putter has poured lead inserts held in place by cured epoxy mixed with the molten lead. This is another very complicated head to machine from a casting. The single alignment marking on this putter is a notch placed above a circular indicia.
U.S. Pat. No. 3,966,210 to Rozmus, John J. (Jan. 29, 1976): Two other heel-toe weighted putter head with hosel (and the problems associated with hosels) are described in Rozmus (U.S. Pat. No. 3,966,210). The heel-toe insert weights in these putter heads are placed at the extreme point away from the striking face, thus, these putters have a pronounced face balanced design. The inserts are in so-called wings so that the putter has either many surfaces to machine or many compound surfaces to finish.
U.S. Pat. No. 5,058,895 to Igarashi, Lawrence Y. (Oct. 22, 1991): An investment casting golf putter head and a driver head are described in Igarashi (U.S. Pat. No. 5,058,895). This putter head has its weighting high above the centerline of the ball striking surface; more over-spin is claimed, however, the shaft must bend for this to occur, which appears unlikely.
U.S. Pat. No. 5,601,499 to Seagline, Frank W. (Feb. 11, 1997): In Seagline (U.S. Pat. No. 5,601,499) a non-insert, cavity backed golf putter is described with a J-shaped cross section. The J-shape forms the sole of the putter. No mention of inserts or of balance is made, but this putter appears to be face balanced with a bent shaft attached to the body.
U.S. Pat. No. 5,439,222 to Kraneberg, Christian F. (Aug. 8, 1995): Kraneberg (U.S. Pat No. 5,439,222) describes another single putting face, hosel equipped golf putter. The inertia increasing inserts are located behind the putting face. Mention is made for varying the inertia without varying the balance; no mention is made for keeping the same balance with different shaft lofts and lies. In addition the Kinoshita invention uses mass insert cavities machined in the face of the putter head opposite to the putting face. The insert cavities are sealed by plugs screwed into the putter body.
The referenced golf putter head inventions in the above do not simultaneously meet the objectives of manufacturability, and versatility of design, dynamics, alignment, and style. Described below is a golf head manufacturing process and golf head design which achieves the following objectives with the following advantages.
My invention can reduce torque from the impact of a golf ball, promote accurate alignment of a golf putter with the objective line, allow multiple putter configurations for shape, mass, loft, and lie from the same basic putter cross-section, which can be made economically and simply from material extrusions.
The United States Golf Association (USGA) restricts the design of golf club woods and irons to remain conventional in design. The fewer restrictions on golf putters allow for more radical approaches to meet the no-twist objective. My golf putter head design can minimize the effects of a twisting moment by departing significantly from the conventional approaches of golf putter designs. Further, my design includes features to help align the club head face perpendicular to the intended trajectory. Also the golf putter head design described herein provides a unique approach to marrying manufacturing and design.
My invention can reduce the number of machining steps necessary to manufacture billet-like golf clubs without resorting to casting. The present invention provides for the reduction in machining steps by extruding a near-net shape of the club head. Fewer machining steps are required to fully achieve a xe2x80x9cfully machinedxe2x80x9d club head when using near-net shape extrusions of any part. In fact, a putter head according to my invention can be formed from as little as two steps: cutting the extruded material to a desired width to form a putter head and machining a shaft hole.
The present invention provides the alignment of the grain structure of the club head by using near-net shape extrusions which are pulled (stretched) immediately after extrusion. The stretching of the extrusion further defines the grain structure of the extrusion beyond that of the as-extruded shape and this process further uniformly achieves material properties from extrusion bar to extrusion bar.
The present invention provides for the alteration of the width of the club head from the same extrusion to suit different applications and club mass. Different cross sections of the club heads are also provided for by the low cost ($100s) manufacturing of a new extrusion die.
Different placements of the club shaft for different applications are provided for in the present invention. Different shaft placements allow different club balancing, such as center balance, face balance, quarter balance, heel, toe, etc., balance from the same extrusion.
Also provided for is bulk surface coating for all but the putting face in the present invention. Bulk surface coating, such as anodizing or powder coating, on long extrusion lengths many times the width of an individual club head reduces the cost of applying the coating and provides for a uniform coating as well.
The current invention provides for the machining of different face slopes (loft angle or loft) from the same extrusion blank. Since the width may also be altered, the same mass head may be manufactured even for different face lofts.
Provisions are made for machining different club shaft slopes (lie angle or lie) in this invention from the same extrusion blank. The club shaft may be located in different locations on the club head. These different locations allow the same club balance if the lie angle is changes. Further, the different shaft locations provide for attaching and locating different club shaft styles, including straight shafts and one, two, or more bend shafts.
The present invention provides for one or two faced golf putter heads from the same extrusion blank. Other one face embodiments, if conforming to USGA rules, may have different shapes from the same extrusion blank, but they are restricted to one club face.
Provisions are made from the present invention to achieve different near-net shape (or machined) embodiments of convex curved sole, concave sole, cavity backed, or other mass altering configurations of the club head from the same extrusion blanks.
Although the extrusion process is used to produce one or more axis of symmetry, provisions are made for the machining away of this axis of symmetry (as for a face-to-face curvature of the club sole or different cavities in the heel, toe, sole, top or faces) while still retaining the benefits of low cost production of uniform property material.
The present invention provides for symmetric toe-to-heel embodiments so that single face club heads may be machined either left-handed or right-handed from the same extrusion blank. The symmetry also provides for machining of left and right hand club heads in exactly the same manner including the machining of the shaft hole with just an appropriate shaft hole offset.
Provisions are made for extruding the mass and inertia altering cavities for weight inserts directly into the extrusion. If these cavities are extruded the steps required to machine them are eliminated.
The present invention allows for altering the material of the club head to any extrudeable material including alloys of aluminum, magnesium, plastics (with or without strengthening fibers), low carbon steel, stainless steel, copper alloys, titanium and more. Further, plastics may be pulled through an extrusion die (pultrusion) with carbon fiber or glass or other suitable reinforcing material.
The locking of the mass and inertia increasing inserts is provide for in this invention by the double tapering of the inserts"" cylinders from the outer diameters (at the club faces) to the interior of the club head. The placement of the inserts in different location of the club head using this locking method is also provided for in this invention.
The present invention provides for achieving a high inertia-to-mass ratio club head by either using high density inserts or head design (like cavity backed) or both in the same low cost material extrusion blank style.
Further provided is a consistent look (finish and surface uniformity) and feel (density, inertia, mass, center of gravity) in this invention by using extruded shapes with consistent material, size and surface properties. The basic advantage of using extrusions in a highly controlled process is used to achieve the invention advantages outlined above. Further, the same advantages can be extended to the manufacturing of other golf club heads from extrusions; for example golf club woods and golf club irons can be extruded.
Still further objects and advantages will become apparent from a consideration of the ensuing description and accompanying drawings.